/* Copyright 2013-2015 www.snakerflow.com.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.snaker.engine.access.jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.snaker.engine.DBAccess;
import org.snaker.engine.SnakerException;
import org.snaker.engine.access.AbstractDBAccess;
import org.snaker.engine.entity.Process;
import org.snaker.engine.helper.ClassHelper;

/**
 * JDBC方式的数据库访问
 * 在无事务控制的情况下，使用cglib的拦截器+ThreadLocale控制
 * @see org.snaker.engine.access.transaction.DataSourceTransactionInterceptor
 * @author yuqs
 * @since 1.0
 */
public class JdbcAccess extends AbstractDBAccess implements DBAccess {
    private static final Logger log = LoggerFactory.getLogger(JdbcAccess.class);
    /**
     * dbutils的QueryRunner对象
     */
    private final QueryRunner runner = new QueryRunner(true);

    /**
     * jdbc的数据源
     */
    protected DataSource dataSource;

    /**
     * setter
     * @param dataSource
     */
    public void setDataSource(final DataSource dataSource) {
        this.dataSource = dataSource;
    }

    @Override
    public void initialize(final Object accessObject) {
        if (accessObject == null) {
            return;
        }
        if (accessObject instanceof DataSource) {
            this.dataSource = (DataSource) accessObject;
        }
    }

    /**
     * 返回数据库连接对象
     * @return
     * @throws java.sql.SQLException
     */
    @Override
    protected Connection getConnection() throws SQLException {
        return JdbcHelper.getConnection(dataSource);
    }

    /**
     * 使用原生JDBC操作BLOB字段
     */
    @Override
    public void saveProcess(final Process process) {
        super.saveProcess(process);
        if (process.getBytes() != null) {
            Connection conn = null;
            PreparedStatement pstmt = null;
            try {
                conn = getConnection();
                pstmt = conn.prepareStatement(PROCESS_UPDATE_BLOB);
                pstmt.setBytes(1, process.getBytes());
                pstmt.setString(2, process.getId());
                pstmt.execute();
            }
            catch (final Exception e) {
                throw new SnakerException(e.getMessage(), e.getCause());
            }
            finally {
                try {
                    JdbcHelper.close(pstmt);
                }
                catch (final SQLException e) {
                    throw new SnakerException(e.getMessage(), e.getCause());
                }
            }
        }
    }

    /**
     * 使用原生JDBC操作BLOB字段
     */
    @Override
    public void updateProcess(final Process process) {
        super.updateProcess(process);
        if (process.getBytes() != null) {
            Connection conn = null;
            PreparedStatement pstmt = null;
            try {
                conn = getConnection();
                pstmt = conn.prepareStatement(PROCESS_UPDATE_BLOB);
                pstmt.setBytes(1, process.getBytes());
                pstmt.setString(2, process.getId());
                pstmt.execute();
            }
            catch (final Exception e) {
                throw new SnakerException(e.getMessage(), e.getCause());
            }
            finally {
                try {
                    JdbcHelper.close(pstmt);
                }
                catch (final SQLException e) {
                    throw new SnakerException(e.getMessage(), e.getCause());
                }
            }
        }
    }

    /**
     * 查询指定列
     * @param column 结果集的列索引号
     * @param sql sql语句
     * @param params 查询参数
     * @return 指定列的结果对象
     */
    public Object query(final int column, final String sql, final Object... params) {
        Object result;
        try {
            if (log.isDebugEnabled()) {
                log.debug("查询单列数据=\n" + sql);
            }
            result = runner.query(getConnection(), sql, new ScalarHandler(column), params);
        }
        catch (final SQLException e) {
            log.error(e.getMessage(), e);
            throw new RuntimeException(e.getMessage(), e);
        }
        return result;
    }

    @Override
    public Integer getLatestProcessVersion(final String name, final Long custNo) {
        final String where = " where name = ? and cust_No = ?";
        final Object result = query(1, QUERY_VERSION + where, name, custNo);
        return new Long(ClassHelper.castLong(result)).intValue();
    }

    @Override
    public boolean isORM() {
        return false;
    }

    @Override
    public void saveOrUpdate(final Map<String, Object> map) {
        final String sql = (String) map.get(KEY_SQL);
        final Object[] args = (Object[]) map.get(KEY_ARGS);
        try {
            if (log.isDebugEnabled()) {
                log.debug("增删改数据(需手动提交事务)=\n" + sql);
            }
            runner.update(getConnection(), sql, args);
        }
        catch (final SQLException e) {
            log.error(e.getMessage(), e);
            throw new RuntimeException(e.getMessage(), e);
        }
    }

    @Override
    public <T> T queryObject(final Class<T> clazz, final String sql, final Object... args) {
        List<T> result = null;
        try {
            if (log.isDebugEnabled()) {
                log.debug("查询单条记录=\n" + sql);
            }
            result = runner.query(getConnection(), sql, new BeanPropertyHandler<T>(clazz), args);
            return JdbcHelper.requiredSingleResult(result);
        }
        catch (final SQLException e) {
            log.error(e.getMessage(), e);
            return null;
        }
    }

    @Override
    public <T> List<T> queryList(final Class<T> clazz, final String sql, final Object... args) {
        try {
            if (log.isDebugEnabled()) {
                log.debug("查询多条记录=\n" + sql);
            }
            return runner.query(getConnection(), sql, new BeanPropertyHandler<T>(clazz), args);
        }
        catch (final SQLException e) {
            log.error(e.getMessage(), e);
            return Collections.emptyList();
        }
    }

    @Override
    public Object queryCount(final String sql, final Object... args) {
        return query(1, sql, args);
    }
}
